Armour Thyroid is a natural supplement derived from powdered animal thyroids that contains T4 and T3 hormone. Synthroid is a synthetic thyroid hormone. Both of these are used to treat hypothyroidism and other thyroid conditions.
Synthroid is a synthetic thryoid replacement made is a lab. Armour thyroid is a naturally made thryoid replacement. Because synthroid is made in a lab its ingredients are constant. Armour thyroid since it is a natural replacement may differ from pill to pill. Synthroid is cheaper than Armour thyroid.
Armour thyroid comes from dessicated pig thyroids and Synthroid is a synthetic version of the thyroid hormone. People tend to have better success with the natural version.
Synthroid is a synthetic medication. Armour Thyroid is a natural medicine. Armour contain both T4 and T3 while synthroid only contains T3 and another synthetic medication would need to be prescribed to give your body T4. Either of these medications are regulated by the federal government and have to meet their guidelines.